Back hoe tooth structure



Filed June 2,

2 Sheets-Sheet l lA/VE/VTOE FPEDD/E U. HA YA/E" May 19, 1970 v F.J. HAYNES ETAI. 13,512,284

"B-ACK HOE TOOTH STRUCTURE Filed June 2, 1969 2 Sheets-Sheet 2 /l 7 20 25 aaQ /sa vz IELET- L IEI'lE-EB /A/ MEN 7' 0/9. Fee/2mg (A H4 wvss United States Patent 3,512,284 BACK HOE TOOTH STRUCTURE Freddie J. Haynes, Midwest City, Okla. (3612 Meadowbrook, Oklahoma City, Okla. 73110) Continuation-impart of application Ser. No. 722,990, Apr. 22, 1968. This application June 2, 1969, Ser.

Int. Cl. E02f 9/28 U.S. Cl. 37-141 12 Claims ABSTRACT OF THE DISCLOSURE A tooth structure for use in a back hoe of the type having power driven reciprocating teeth, the tooth structure including a pyramidally shaped point formed integrally with a rectangularly cross-sectioned base portion, and a drive rod member detachably secured to the base portion. The drive rod member includes a head portion having a protuberant connector stud which registers with a complementary socket in the base portion of the tooth structure in which the stud is detachably retained. An elongated rod is secured to the head portion of the drive rod member. The head portion of the drive rod member is rectangularly cross-sectioned, and at its point of connection to the drive rod, is characterized in having a dirt displacement face which extends at an angle to a plane extending normal to the longitudinal axis of the elongated rod.

In a different aspect of the invention, a plurality of the described tooth structures are reciprocably mounted on a dirt receiving bucket in juxtaposition to each other. The bucket has a digging leading edge which carries a face plate, and the elongated rods of the drive rod members are mounted for reciprocation through the face plate so that the longitudinal axis of each rod extends substantially normal to the major plane of the face plate.

RELATED APPLICATIONS This application is a continuation-in-part of Freddie I. Haynes U.S. patent application Ser. No. 722,990 entitled Back Hoe Apparatus filed Apr. 22, 1968, now Patent No. 3,448,535.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to earth moving equipment, and more particularly, to back hoe structures having a plurality of movable teeth mounted at the digging edge thereof.

Brief description of the prior art Back hoes having powered teeth have been heretofore proposed and manufactured. Where the teeth of the back hoe are driven in reciprocation in relation to a leading, digging edge of the bucket of the hoe, a problem exists of preventing dirt impaction between the teeth, or between the teeth and the bucket to the extent that the excavating efiiciency of the bucket is impaired. It is also desirable that the teeth on such back hoes be of mechanically strong construction, and it is preferred that such teeth be replaceable quickly by new teeth if they should become damaged.

A back hoe having powered, reciprocating teeth is described in my co-pending application Ser. No. 722,990 of which this application is a continuation-in-part. The present invention is an improvement in the tooth structure used in such back hoes, and specifically, though not exclusively, in back hoes of the type descrbied and depicted in the cited patent application.

Brief description of the present invention The back hoe tooth structure ofthe present invention can be broadly described as including a point secured to, or formed integrally with, a base portion, and a drive rod member which is detachably connected to said base portion. Replacement of damaged points is thus facilitated. The drive rod member includes a head portion having a protuberant connector stud extending from one side thereof for connection to the base portion, and having an elongated rod connected to the opposite side of the head portion from the protuberant connector stud. The head portion of the drive rod member is characterized in having a dirt displacement face which extends at an acute angle to a plane extending normal to the longitudinal axis of the elongated rod.

In a more comprehensive aspect, the present invention relates to the combination of a plurality of the described tooth structures with a back hoe bucket. In this com bination, the tooth structures are reciprocably mounted in juxtaposition to each other on the dirt engaging leading edge of the bucket. The bucket is characterized in having a face plate mounted at such leading edge through which the elongated rods of the drive rod members of the teeth are extended. The longitudinal axis of each elongated rod extends substantially normal to the face plate so that the dirt displacement faces of the head portions of the tooth structures each extend at an acute angle with respect to the plane of the face plate. This permits dirt and foreign matter to be more easily ejected from the space between the head portion of each tooth structure and the face plate during the retraction of the point of the tooth. The rod of each tooth structure drivingly engages a cam shaft which is rotatably mounted in a sealed chamber beneath the dirt supporting surface of the bucket.

From the foregoing description of the invention, it will be apparent that an object of the invention is to provide an improved tooth structure for use on back hoes which include structure for powering the teeth in a reciprocating movement.

Another object of the invention is to provide a tooth structure for use on back hoes, which tooth structure can be quickly replaced when damaged.

An additional object of the invention is to provide a back hoe apparatus having powered teeth which operate relatively freely of dirt impaction.

Additional objects and advantages of the invention will become apparent from the following detailed description of the invention when it is considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a back hoe bucket constructed in accordance with the present invention.

FIG. 2 is a sectional view taken along line 22 of FIG. 1.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is a sectional view taken along line 44 of FIG. 1.

FIG. 5 is a sectional view taken along line 55 of FIG. 2.

FIG. 6 is an exploded view of the tooth structure of the invention.

FIG. 7 is a perspective view of a tooth point and base portion forming a part of the tooth structure of the invention.

FIG. 8 is a perspective view of the drive rod member forming a part of the tooth structure of the invention.

3 DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring initially to the drawings, and in particular, to FIG. 1, shown therein is a back hoe bucket designated generally by reference numeral 10. The back hoe bucket 10 is connected by a suitable connection bracket 12 to the boom structure (not shown) of a back hoe in the manner illustrated and described in my co-pending application Ser. No. 722,990 filed Apr. 22, 1968, and entitled Back Hoe Apparatus Having Movable Teet The back hoe bucket 10 is constructed similarly to that described in said co-pending application and thus includes a pair of substantially parallel side walls 14, a dirt-carrying bottom wall 16 and an arcuate or curved back wall 18 which is preferably formed integrally with the dirt-carrying bottom wall 16. The bucket 10 further includes a lower chamber wall 20 which, with the dirtcarrying bottom wall 16 and the lower portions of the side walls 14, forms an open receiving chamber 22 which is open at its front end and at its back end. A removable arcuate closure plate 24 is constructed with a curvature in transverse dimension which perits it to be fitted to the lower portion of the bucket 10 in the manner best depicted in FIG. 2. Thus, the arcuate closure plate 24 has its forward edge secured to the rear edge of the lower chamber wall 20, and has its rear edge secured to the lower edge of the arcuate back wall 18 of the bucket.

Positioned within the open receiving chamber 22 is a removable sealed driving unit designated generally by reference numeral 26. The sealed driving unit 26 includes a casting block 28 which is an integrally cast element constructed to accommodate a prime mover, elongated drive rods connected to the digging teeth, and a cam shaft, all as more specifically described in co-pending US. application Ser. No. 722,990 to which reference has hereinbefore been made. Thus, the casting block 28 may be constructed with a transversely extending well 30 formed therein for the accommodation of a hydraulic motor 32. The hydraulic motor 32 receives power fluid from a pair of hydraulic fluid supply conduits 34 and 36 which are connected through suitable fluid tight fittings 37 extending through the rear wall of the casting block 28.

A cam shaft housing 38 is formed as a portion of the casting block 25 and is located in the central portion of the casting block. The cam shaft housing 38 is bored over its length to receive an elongated, generally cylindrical cam shaft 40 which is rotatably mounted in the described bore by means of a plurality of suitable bearing elements 42 (see FIG. A portion of the cam shaft housing 38 at the center thereof is cut away to accommodate a driving chain 44 from the hydraulic motor 32, which driving chain is extended around a suitable sprocket 46 keyed to the cam shaft 40.

The details of construction of the cam shaft 40 are set forth in my co-pending application Ser. No. 722,990. It will suflice for purposes of explaining the present invention to point out that the cam shaft has cam surfaces spaced longitudinally therealong, which cam surfaces drivingly contact a plurality of horizontally spaced, elongated rods 50 forming portions of drive rod members designated generally by reference numeral 52. Each drive rod member 52 further includes a head portion 54 which has formed integrally therewith, or suitably secured thereto, a protuberant connector stud 56 which projects horizontally from the head portion 54 on the opposite side thereof from the elongated rod 50. Each of the elongated rods 50 extends through an annular sealing ring 58 and a tubular bushing 60. The tubular bushings 60 are positioned in bores formed through the casting block 28.

Extending across the front edge of the bucket between the side walls 14, and between the dirt-carrying bottom wall 16 and the lower chamber wall is a 4 face plate 62. Disposed between the face plate 62 and the parallel forward face of the casting block 28 is a sealing gasket 64. It will be noted that the elongated rods 50 are each extended through aligned or registering apertures or openings formed through the face plate 62 and the sealing gasket 64.

For the purpose of limiting the reciprocating movement of each of the elongated rods 50 within its respective bushing 60, a motion limiting pin 66 is extended through the dirt-carrying bottom wall 16, through a rigid cover plate 68 which is extended across the top of the casting block to close the cavity containing the hydraulic motor 32, through a sealing gasket 70, through the casting block 28 through the bushing 60 and into a longitudinally extending slot 72 formed in the upper side of the respective rod 50.

The remaining portion of the back hoe tooth structure of the invention is the leading portion of the tooth structure which includes a pyramidally shaped point 74 which is formed integrally with, or secured to, a rectangularly cross-sectioned base portion 76. It will be noted in referring to the point 74 of the tooth structure that the four side faces of the point are triangular, and that the bottom or lower face of the point is inclined upwardly slightly with respect to the horizontal (see FIG. 4). It will also be noted in referring to FIG. 3 of the drawings that the upper faces of the points 74 constitute isosceles triangles, and that the base portions 76 of the several tooth structures are located in juxtaposition to each other so that very little dirt can pass between the base portions during operation of the back hoe in the manner hereinafter described.

The base portion 76 of the tooth structure of the invention is of generally rectangular configuration in vertical cross-section, and is secured to the base or large area portion of the point 74. Preferably, the base portion 76 is formed integrally with the point 74, and is of substantially the same cross-sectional area in vertical cross-section as is the area of the base of the pyramidally shaped point. The base portion 76 has a planar, substantially vertically extending face 78 on the opposite side thereof from the point 74 and extending into the base portion 76 from this face is a generally rectangularly cross-sectioned socket 84. The socket 84 extends substantially horizontally, and is dimensioned to receive the protuberant connector stud 56 which projects horizontally from the head portion 54 of the drive rod member 52. The protuberant connector stud is, of course, of a cross-sectional configuration to mate with the socket 84.

A vertically extending pin aperture 86 extends downwardly through the bas portion 76 of the tooth structure and registers ith a pin aperture 88 formed in the protuberant connector stud 56 when the connector stud is forced into the socket 84 formed in the base portion 76. An elongated securing pin 90 is then driven downwardly through the aligned apertures 86 and 88 to lock the drive rod member 52 to the base portion 76 of the tooth structure. The tooth structures when thus assembled, appear as shown in FIGS. 4 and 5.

It will be noted that the head portion 54 of the drive rod member 52 includes a substantially vertically extending planar face 54a which carries the protuberant connector stud 56 and a rear face 54b which extends substantially parallel to the face 54a and which has secured therto, the elongated rod 50. A pair of tapered dirt displacement faces 540 and 540! which are inclined at an acute angle with respect to the vertical intersect the face 54b and complete the formation of the back side of the head portion 54. It will be noted in referring to FIG. 4 that the dirt displacement faces 54c and 54d extend at an acute angle with respect to the plane of the face plate 62 or, stated differently, extend at an acute angle with respect to a plane extending normal to the longitudinal axes of the elongated rods 50.

OPERATION In the operation of the improved back hoe which incorporates the tooth structure of the present invention, the hydraulic motor 32 is driven by hydraulic power fluid delivered by one of the conduits 34 or 36 and discharged through the other of these conduits. As the hydraulic motor 32 is driven in rotation, the driving chain 44 is driven to cause the sprocket 46 keyed to the cam shaft 40 to be driven in rotation. The rotation of the cam shaft 40 in the bearings 42 causes the cam surfaces longitudinally along this cam shaft to contact the free ends of the elongated rods 50 forming a portion of the drive rod members 52. As the high points on the cam surfaces of the cam shaft 40 move across the end faces of the elongated rods 72, these rods are caused to reciprocate within the bushings 60. The elongated rods 50 thus move outwardly and push before them, the head portion 54 of each of the drive rod members 52. The cam surfaces formed on the cam shaft 40 are circumferentially staggered around the cam shaft so that the drive rod members are reciprocated out of phase with each other. This action is explained in greater detail in my co-pending U.S. application Ser. No. 722,990, to which reference has hereinbefore been made.

As the drive rod members 52 are reciprocated in the bushings 60, they are extended outwardly through the openings in the face plate 62. The stroke of each tooth structure is limited by the configuration of the cam surfaces on the cam shaft 40, and by the movement limiting function of the motion limiting pins 66. After reaching the outer end of its stroke, each tooth structure will be bearing against the earth ahead of the bucket 10, and as the buck is moved toward this earth, a force is brought to bear on the point 74 of the tooth structure tending to force the tooth structure back in a retractive movement. The retractive movement is permitted by the configuration of the cam surface on the cam shaft 40.

During the retractive movement, each elongated rod 50 moves inwardly within the bushing 60 and the head portion 54 of the drive rod member moves to a position adjacent the face plate 62. It will be noted that the inclined dirt displacement faces 54c and 54d of each head portion 54 of each drive rod member 52 are, at this time, inclined at an acute angle with respective to the plane of the face plate '62. The effect of this inclination is to develop a wedging action tending to wedge or force outwardly from between the head portion 54 and the face plate 62, any dirt which may tend to pass between the'head portion and the face plate. Dirt accumulation and impaction in this area are thus prevented by this configuration of the side of the head portion 54 to which the elongated rod 50 is connected.

At such time as the point 74 of a tooth structure may become damaged or blunted, such point may be quickly and easily replaced by simply removing the securing pin 90 which passes through the aligned or registered pin apertures 86 and 88. This will permit the point 74 and base portion 76 to be pried off of the protuberant connector stud 56 which extends into the socket 84 formed in the base portion 76. A new tooth point and base portion can then be quickly replaced on the drive rod member 52 by forcing the protuberant connector stud 56 into the socket 84, and then driving the securing pin 90 into position through the registering pin apertures 86 and 88.

What is claimed is:

1. In a back hoe of the type having a bucket, teeth reciprocably mounted at one edge of the bucket, and means mounted on the bucket for driving the teeth in reciprocation, the improved tooth structure characteristic of each of said teeth which comprises:

a pyramidally shaped point;

a rectangularly cross-sectioned base portion secured to said pyramidally shaped point; and

a drive rod member detachably secured to the base portion, said drive rod member comprising:

a head portion;

a protuberant connector stud projecting from one side of said head portion and connecting said head portion to said rectangularly cross-sectioned base portion; and

an elongated rod connected to the opposite side of said head portion from said protuberant connector stud, said head portion having at least one dirt displacement face adjacent the point of connection of said elongated rod thereto, said dirt displacement face extending at an acute angle with respect to the longiutdinal axis of said elongated rod.

2. The improvement in a back hoe defined in claim 1 wherein said base portion has a socket extending thereinto from the side thereof opposite said pyramidally shaped point, and wherein said protuberant connector stud extends into, and engages, said socket.

3. The improvement in a back hoe defined in claim 2 wherein the head portions of said drive rod members are positioned in juxtaposition to each other when all of said drive rod members are in transverse, horizontal alignment.

4. The improvement in a back hoe defined in claim 2 wherein there are a pair of said dirt displacement faces disposed on opposite sides of said elongated rod.

5. The improvement in a back hoe defined in claim 2 wherein said connector stud has a pin aperture formed therethrough, and said head portion has a pin aperture therethrough aligned with the pin aperture formed through said connector stud, and wherein said stud is connected to said head portion by a pin extended through said aligned pin apertures.

6. The improvement in a back hoe defined in claim 2 wherein said point has upper and lower faces shaped as isosceles triangles.

7. The improvement in a back hoe defined in claim 5 wherein there are a pair of said dirt displacement faces disposed on opposite sides of said elongated rod.

8. A back hoe bucket comprising:

a pair of opposed, horizontally spaced side walls;

a dirtl-carrying bottom wall extending between the side we Is;

a back wall extending between the side walls;

a lower chamber wall extending between the side walls and spaced downwardly from the bottom wall, and defining therewith an open receiving chamber;

a removable sealed driving unit positioned within said open receiving chamber;

a face plate secured between said side Walls and between said dirt-carrying bottom wall and said lower chamber wall and closing one side of said open receiving chamber; and

a plurality of horizontally aligned tooth structures mounted through said face plate, each of said tooth structures comprising:

a pyramidally shaped point;

a rectangularly cross-sectioned base portion secured to said pyramidally shaped point; and

a drive rod member detachably secured to the base portion, said drive rod member comprismg:

a head portion having a vertical cross-section which is rectangular in configuration;

a protuberant connector stud projecting from one side of said head portion and connecting said head portion to said rectangularly cross-sectioned base portion, said one side of said head portion from which said connector stud projects being planar and extending substantially parallel to said face plate; and

an elongated rod connected to the opposite side of said head portion from said one side from which said protuberant connector stud projects, said head portion having at least one dirt displacement face adjacent the point of connection of said elongated rod thereto, said dirt displacement faee eX- tending at an acute angle with respect to said face plate.

9. A back hoe bucket as defined in claim 8 wherein said removable, sealed driving unit contains:

a prime mover;

a cam shaft;

\means drivingly connecting said prime mover to said cam shaft, said cam shaft being positioned for contacting and reciprocably driving said elongated rod of said tooth structure.

19. A back hoe bucket as defined in claim 9 wherein said face portion of each of said tooth structures has a socket extending thereinto from the side there-cf opposite said pyramidally shaped point, and wherein said proturberant connector stud extends into, and engages, said socket.

11. A back hoe bucket as defined in claim 9 wherein said head portion of said drive rod members are positioned in juxtaposition to each other when all of said 8 drive rod members are in transverse, horizontal alignment.

12. A back hoe bucket as defined in claim 11 wherein there are a pair of said dirt displacement faces disposed on said opposite sides of said elongated rod and on the opposite side of said head portion from said one side from which the said protuberant connector stud projects.

References Cited UNITED STATES PATENTS 309,553 12/1884 Manning 37142 1,009,254 11/1911 McKenzie 37--141 2,113,420 4/1938 Younie 3714l 3,027,027 3/ 1962 Bles 37142 X'R 3,117,386 1/1964 Ferwerda 37--142 3,272,559 9/1966 Haynes 37-141 XR 3,436,849 4/1969 Haynes 37141 3,448,535 6/1969 Haynes 37-l41 FOREIGN PATENTS 18,543 11/ 1897 Great Britain.

EDGAR S. BURR, Primary Examiner US. Cl. X.R. 37142 

